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Use of coating particle film to modulate leaf temperature and heat stress on citrus trees

Grant number: 20/05381-6
Support type:Scholarships in Brazil - Master
Effective date (Start): January 01, 2021
Effective date (End): December 31, 2022
Field of knowledge:Agronomical Sciences - Agronomy - Soil Science
Principal Investigator:Dirceu de Mattos Junior
Grantee:Lucas Giovani Pastore Bernardi
Home Institution: Instituto Agronômico (IAC). Agência Paulista de Tecnologia dos Agronegócios (APTA). Secretaria de Agricultura e Abastecimento (São Paulo - Estado). Campinas , SP, Brazil


Extreme weather conditions, such as high irradiance and high air temperature, cause disturbances to plants and impact the production and quality of fruits. The citrus is an important chain of world agriculture, which requires a constant increase in production efficiency within high levels of sustainability. Under stress, flowering and fruiting of citrus trees are injured, among which, excess UV radiation affects plant photosynthesis. Also, the high air temperature causes an increase in the production of reactive oxygen species (ROS) that damage the plant structure. Commercial products, such as coating particle films against high irradiance, have been developed to minimize these losses and optimize production in the field, given the climate change scenario. However, accurate information is not available for their use. Thus, we seek to evaluate the particle distribution of two protective films, of the type kaolin and calcium oxide-carbonate, on the leaf surface under light microscopy, and the effects of its application on the cuticle and on the anatomical arrangement of the leaf blade, compared with two control treatments without the film (varying irradiance), characterize the concentration and distribution of mineral elements by chemical analysis of total nutrients, EDX and XRF, determine the balance of antioxidant compounds and oxidative stress products in the leaf tissue and the efficiency of the photosynthetic apparatus. The experiment will be conducted outdoors, with four treatments: T1: Full sun control (sprayed with water), T2: Reduced irradiance control, under anti-UV transparent plastic (sprayed with water), T3: pulverized kaolin [wettable powder, 1 µm (30 g L-1)] and T4: pulverized calcium oxide-carbonate [wettable powder, <1 µm (30 g L-1)], with 6 repetitions per treatment, represented by a plant. The treatments will be applied about 15 days before the period of greatest irradiance and high air temperature (October and November) with evaluations carried out for up to 30 days. ANOVA will be performed for each variable evaluated, and when significant, the Tukey test, with a 95% confidence interval will be used. (AU)